X TABLE OF CONTENTS. 



Chemistry of alkaline natural waters 21 



Relations of the soil to potash-salts and phosphates 22 



Origin of insoluble metallic sulphides 23 



Deoxidation of metals, sulphur, and carbon through vegetation . . 23 



Twofold origin of carbonates of lime and magnesia .... 23 



The two types of igneous rocks ; their sedimentary origin ... 24 



Rock-metamorphism defined and distinguished from pseudomorphism 24 



Relation of alkaline waters to crystalline silicates 25 



Local metamorphism ; views of Daubre*e and Naumann ... 26 



Progressive change in silico-aluminous sediments 27 



Chemical relations of certain mineral silicates 28 



Various series of crystalline stratified rocks 29 



Laurentian, Labrador, Green Mountain, and White Mountain series . 30 



The hypothetical granitic substratum ; granitic veins .... 33 



Crystalline rocks of Europe and North America compared ... 34 



IV. 



THE CHEMISTRY OF THE PRIMEVAL EARTH (1867). 



The spectroscope and the nebular hypothesis 35 



Dissociation defined ; terrestrial chemical elements .... 37 



Probable existence of more elemental forms of matter in the stars . . 37 



Chemical and physical constitution of the sun 37 



Chemical history of the cooling earth 38 



Probable solidification from the centre 39 



Primitive atmosphere and ocean ; their composition 40 



Their action on the primitive crust 40 



Mutual relations of carbonic acid, clay, limestone, and sea-salt . . 41 



Waters of the ancient ocean 41 



Carbonic acid of the ancient atmosphere 42 



Its relations to life and to climate 42 



Formation of gypsums and magnesian limestones 43 



Secondary and aqueous origin of granites 43 



Action of internal heat; volcanoes 44 



Hopkins, Pratt, and Sir William Thomson on the earth's interior . 45 



Controversies of the neptunists and plutonists 45 



APPENDIX. 



The earth's climate in former ages 46 



Tyndall on the relation of gases and vapors to radiant heat ... 46 



Former predominance of carbonic acid in the air 47 



Note on the amount of carbonic acid now fixed in limestones . . 47 



V. 

 THE ORIGIN OF MOUNTAINS (1861). 



Hall on palaeozoic sediments in eastern North America .... 49 



Eastern origin of these mechanical sediments 49 



